The present invention relates to a counterbalanced flex window adapted to be opened by means of the sashes thereof flexing and foldably closing upon themselves about a joining hinge. The advantage of such a window, when sashes thereof are releasable from both the top and bottom, is that one may position the same so as to enable access from inside to clean both the interior and exterior surfaces of the window sash panes.
Exemplary of flex window teachings are those as set forth in U.S. Pat. No. 2,330,696 to Exiner dated Sep. 28, 1943, and U.S. Pat. No. 2,771,133 to Haskell dated Nov. 20, 1956. As is typical of prior art flex window structures, however, and as respectively shown in each of the foregoing references, some sort of a mechanical holding or latching means is necessary to retain set of the foldably opened sashes of a flex window in an opened position as opposed to the employment of a conventional counterbalancing means. In both Exiner and Haskell mechanical locking devices are employed to hold the foldably opened sashes in a fixed position. On the other hand, in a teaching by Dawes in U.S. Pat. No. 2,408,739 dated Oct. 8, 1946, the flex window sash is not only foldably opened and operated, but held as well also in a fixed position by means of a pivotally connected threaded collar vertically driven by a crank operated cooperative threaded shaft.
A cam operated balance shoe of that type typically illustrated and described in U.S. Pat. No. 4,683,676 to Sterner, Jr., dated Aug. 4, 1987, in combination with the constant force counterbalance coil spring application as typically described and taught in U.S. Pat. No. 4,935,987 Sterner, Jr., dated Jun. 26, 1990, are similar to those generally like components employed by the instant applicant, in combination one with the other and with a flex window structure, in order to provide the automatic counterbalance and opening set capabilities as herein taught.
As contrasted to the foregoing, applicant herein by his invention provides a convenient new and novel means for counterbalancing a flex window so the same may be opened and set at any random position within the range thereof without a need for use of supplemental mechanical hardware means for effecting positive latch engagement and retained sash set at one of a limited range of predetermined positions.